Hori Mayuko, Oka Shyunsuke, Sugie Yoshimi, Ohtsuka Hokuto, Aiba Hirofumi
Laboratory of Molecular Microbiology, Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University.
J Gen Appl Microbiol. 2017 Mar 17;63(1):44-50. doi: 10.2323/jgam.2016.07.005. Epub 2017 Jan 31.
Two-component signal transduction systems (TCS), that are also referred to as His to Asp phosphorelay systems, are involved in widespread cellular responses to diverse signals from bacteria to plants. Previously, we succeeded in reconstructing a cyanobacterial photo-perception system in Escherichia coli by employing a CcaS-CcaR two-component system from Nostoc punctiforme. In this study, we have added a photo-responsive ability to ArcB-ArcA (anoxic redox control) TCS of E. coli by fusing a cyanobacterial photoreceptor domain of CcaS with an intracellular histidine kinase (HK) domain of ArcB. For this, we constructed several chimeric HKs between CcaS and ArcB and found that one chimeric HK, named ArcaS9, has a photo-responsive ability. When ArcaS9 was expressed with an ArcA response regulator in E. coli expressing phycocyanobilin (PCB)-producing enzymes, the expression of sdh, a target gene of ArcB-ArcA TCS was regulated in a light-color-dependent manner. Thus we succeeded in endowing E. coli HK with a photo-responsive ability. This provides an insight into how the sensing ability of HK can be manipulated by a chimeric construct.
双组分信号转导系统（TCS），也被称为组氨酸到天冬氨酸的磷酸化中继系统，参与了从细菌到植物对各种信号的广泛细胞应答。此前，我们通过利用来自点状念珠藻的CcaS-CcaR双组分系统，成功在大肠杆菌中重建了蓝细菌的光感知系统。在本研究中，我们通过将CcaS的蓝细菌光感受器结构域与ArcB的细胞内组氨酸激酶（HK）结构域融合，赋予了大肠杆菌的ArcB-ArcA（缺氧氧化还原控制）双组分系统光响应能力。为此，我们构建了几个CcaS和ArcB之间的嵌合HK，并发现一个名为ArcaS9的嵌合HK具有光响应能力。当ArcaS9与ArcA反应调节因子在表达藻蓝胆素（PCB）产生酶的大肠杆菌中一起表达时，ArcB-ArcA双组分系统的靶基因sdh的表达以光色依赖的方式受到调控。因此，我们成功地赋予了大肠杆菌HK光响应能力。这为通过嵌合构建体操纵HK的传感能力提供了一个思路。
